Lets assume that there is a biometric algorithm for user authentication which compares fingerprints with an user's signature saved in database (comparing function is not important here). Next there is ...

I have a server which has a configured value of AES and HMAC key.
The client also should have the same keys.
When the client sends a request, the server interprets this request and reads the message.
...

Are there any cryptographic schemes/protocols that would allow me to encrypt a file, make it publicly available, but ensure that it can only be decrypted when a specific condition is not present (I ...

I know how to decrypt a file after one or more specific environnemental conditions are met (with secure triggers).
I am interested in a cryptographic sheme that would enable decryption of data only ...

Since the demise of GTalk a few weeks ago, we've found that MIM seems to be the lightest instant messaging client out there. It connects to multiple chat services (MSN, Skype, Yahoo) Our main concern ...

I made an Arduino project to lock and unlock my door via my phone (with Bluetooth). It works well but it’s unsafe since I just send the lock and unlock command in cleartext, without authentication or ...

Since I'm fairly unfamiliar with the specific details of the SSH protocol, I was wondering if it was possible for a compromised SSHd server to upload a malicious payload (like a Trojan or some other ...

I am writing a client / server program pair. I have established my own protocol and am communicating with TCP. Presently, when the client messages the server, it adds 42 to each byte (looping, 127 + 1 ...

Is there a protocol or best practice for trading information between parties where one, after receiving his share of the information from the others, might refuse to answer or might alter his answer, ...

There is an older game that solely uses UDP to communicate, and I wanted to add password authentication to the game to facilitate things like experience points and rankings. To this end, I decided to ...

The default usage of HttpClient and HttpWebRequest .NET classes is setting Credentials property and then asking the class instance to perform an HTTP request. If the target requres Basic authorization ...

I have been using CrashPlan for a while internally (i.e. local backup server). I would also like to setup off-site backup but my experience is that I have to forward a port from the router sitting at ...

Below is an informal protocol narration of a simple authentication protocol. A sends to B a signed hash of message M, B's name and a nonce N. B knows that the message M is intended for him, that it ...